This invention relates to the production of flame-retardant polyols. The inorganic-organic flame-retardant polyols are produced by mixing and reacting an epoxy compound, a phosphorus-containing compound and a compound containing one or more reactive hydrogen atoms that will react with an epoxy compound or phosphorus-containing compound to produce a polyol which contains free phosphorus acid radicals which are reacted with a basic salt-forming compound. Free phosphorus-containing compounds are present in the polyol which are reacted with the basic salt-forming compound to produce inorganic flame-retardant agents.
In the process of U.S. patent application Ser. Nos. 060,492 and 060,502, an inorganic flame-retardant agent is produced and is used in the form of an inorganic flame-retardant agent polyol emulsion in the production of polyurethane and polyester products. In the process of this invention, the phosphorus-containing compound is a part of the polyol compound by reacting it with the epoxy compound and/or the compound containing one or more active hydrogens. The phosphorus-containing compound may also act as the catalyst in the chemical reactions. An excess of the phosphorus-containing compound may be used and inorganic flame-retardant agents are also produced which are in the form of very small particles and are well distributed in the product which makes it an effective and inexpensive flame-retardant agent. This combination of phosphorus-containing polyols containing emulsified inorganic flame-retardant agents makes a very effective and inexpensive flame-retardant polyol which is useful in the production of polyurethane and polyester products.
While not wishing to be bound by any theory of operation, it appears that the basic salt-forming compound and the acidic phosphorus salt-forming compound chemically react in the inorganic-organic polyol liquid, and a much smaller particle is produced which is well distributed in the product and only takes a small amount, such as 2 percent to 10 percent by weight of the flame-retardant agent, to be an effective and inexpensive flame-retardant agent. It takes as much as 3 to 10 times as much more of the phosphorus-containing salt not produced in a polyol. In some reactions, a small amount of water is beneficial in speeding up the reaction and also is beneficial in flame-retardation. A small amount of water is chemically bound to the flame-retardant agent. An amount of water equal to the amount of the phosphorus-containing compound is usually sufficient. An excess should be avoided.